Were
Adam and Eve the first people on earth? What were the fallen angels doing while
Satan was tempting Eve?

The very first
chapter in the Bible, Genesis 1, begins with God creating this planet.
And on the 6th day,
Genesis 1:27 says that
"God created man in His
own image, in the image of God created He him; male and female created He
them." You should
really read through both chapters 1 and 2 to get the whole picture.

The Bible is
clear that Adam was the first person to ever live on this earth and then
Genesis 2:21-22
describes how Eve was formed next: "And the Lord caused a deep sleep
to fall upon Adam, and he slept; and He took one of his ribs, and closed up
the flesh instead thereof; and the rib, which the Lord God had taken from
man, made He a woman, and brought her unto the man."

The New Testament also states in
the genealogy of Jesus that Adam was indeed the first human being. In
Luke 3 verses 23-38,
the ancestry of Christ is traced all the way back to the creation of the
world.

Now for the 2nd part of the question: Unfortunately, the Bible really
doesn't tell us what these fallen angels where doing while Eve was being
tempted. But Revelation 12:9makes it
clear that these angels were evicted out of heaven with Lucifer: "And the great dragon was cast
out, that old serpent, called the Devil, and Satan, which deceiveth the
whole world: he was cast out into the earth, and his angels were cast out
with him."

It's also true
that 1/3 of all the angels of heaven rebelled and sided with the devil.
Revelation 12:4
represents these angels as the "stars of heaven"
and that it was the "tail"
of the great red dragon that pulled them down to this planet. Today,
these angels are what we would call demons or evil spirits.(See Matthew 4:24 and
8:16, Mark 5:1-15, Luke 8:2 and 9:1)

It would only be speculation for
us to state exactly what these angels were doing while Satan was at work in
the garden of Eden, but it's probably safe to say that they were up to no
good!